The support that various types of cushioned furniture, for example, couches, “easy” chairs, beds, etc., provide their occupants often diminish over time through use. This diminished support can manifest itself in a number of ways, such as reduced firmness, visible sag, and lowered seating height, and any combination of these. When any one or more of these conditions are present, the furniture is often otherwise in fine shape, and owners are often loath to replace them or undertake the usually expensive repairs that would be necessary to restore the supportiveness of the furniture to a like-new state. In addition, some users are not always satisfied with the support performance of even new furniture and desire ways of improving the support, for example, firmness or seating height, of the new furniture.